I may have mentioned this before, but the Merian C. Cooper version of Rider Haggard's She is well worth a look. It is wonderfully bonkers. Check this out.
Yes, you heard/saw right. Firstly, Nigel Bruce is in it as Horace Holly, the scientist/mentor of Leo Vincey. Secondly, it is set in the Russian Arctic, not Africa. And thirdly, the sacred flame of Kor is radium shooting out of the earth.
And that's just the start of the hijinks. The actual plot is not too different from that of the book, but it cops out a bit re: Leo's behaviour and his fate. The equivalent to the tragic Ustain in the book is a European orphan raised in a convent, of all things.
Perhaps the best scene is a protracted, massively choreographed dance in the Hall of Kings, which probably features every single performer on RKO's list at the time. Tremendous stuff. Not quite supernatural, thanks to the radium stuff, but a worthy stab at a mystical, powerful, and more than slightly daft classic.